Electric signaling.



G. 0. SQUIER, L. W. AUSTIN & L. COHEN.

ELECTRIC SIGNALING.

APPLICATION FILED AUG.I4. I9I6- Patented Oct. 15,- I918.

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Lo 15 Comm! G. 0. SQUIER, L. AUSTIN & L. COHEN.

ELECTRIC SIGNALING.

APPLICATION FILED AUG. I4. 1916.

Patented Oct. 15, 1918.

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vwewtow, GEORGE O.SQUIER, Lou/6 W. AUSTIN, L UlS 60HEN.

SQUIER,

mnLouIs comm, or WASHIN GTON, ms'rmcr or COLUMBIA.

ELECTRIC SIGNALING.

To all whom it may concern;

Be it known that we, GEORGE OWEN lieutenant col., U. S. Army, LOUIS W.,AUsT1N','and Louis COHEN, all residing at Washington, in the District of Columbia, have invented certain new and useful Improvements in Electric Signaling, of which the following is a specification.

' This invention relates to electrical signali with the cable, or lnterpreted directly in said, system, having the above-described duplex system, one end --ment,'operatively connec is linked electromagnetlcally naling current is to increase the working capacity of'the system, and consists Squier standard duplex this standard duplex in superimposing upon with a sending and at its other end with a receiving instrument, and in which messages are transmitted by unbroken alternatingcurrent of a frequency different from that employed in the duplex system, and 1n'- this interpretation, the simplexsystem the medium of an terpreted, by the ear; where the frequency of requires it, being through oscillating audion system circuit which telephone, where the frequency of the sig-' well within audition. In other words, the frequencies of duplex system and the superimposed simplex circuit may some suitable instrumentality at the receiving end; or the former may be below audition and the latter well within audition, in which case the current of the simplex circuit strumentalities. I The sending current. of each system 1s rendered ineffective in the receivlng equipment of the other 'system'as by counterbalancing transformers at the transmittlng end of the 1 simplex system and by electrical tuning at the receiving end of the simplex system and by having the transmitted current ofthe simplexsystem insuflicient to affect the receiver at the remote end of the duplex sys- Specification of Letters Patent.

in which the messages are transmitted an extra simplexcircuit equipped at I orticker arrange, ted to an oscillating the standard 7 both be belowaudition, the latter being brought Within audition by- Patented Oct, 15, 1918.

Application filed August 14, 1916. Serial a. 114,824.

tem, but sufficient. to operate the more sensitive receiving instruments employed in the simplex system at that end.

Three illustrative embodiments of the invention, differing mainly in the circuit arrangements and devices employed for the superlmposed systemare shown schemati- 'cally in the accompanying drawings and designated respectively asFigures 1, 2 and 3.

In each of the figures, A and B represent two stations at opposite ends of the duplex i electrical signaling system, such for mstance, as the ends of an inter-continental cable system, and in each of these figures, the duplex system is substantially identical v in principle with that'described in British Letters Patent No. 22,265of1914, already referred to; that is to say, at each end of the duplex system, 1 represents a source of alternating current, 2, 3,,thecoils of the transformer by which said; current is impressed upon the line, the primaryof which includes a suitable device 4, forv varying the amplitudeof the wavesof such current and the secondary of which is grounded at 5. 6 represents balancing condensers, 7 the'receiving dev ce, and 8 the artificial cable. These injstrumentalities are duplicated at the ends of thecable 9, and constitute the standard equipment of a duplex system in accordance with said British patent.

The present invention increases the work- GEORGE OWEN semen, or THE UNITED s'rA'rEsAri Y, AND LOUIS WINSLOW AUSTIIiT ing capacity of a cable or other telegraph equipment, by, superimposing upon the line, an extra simplex systemwhlch may consist of the following instrumentalities:

- 10 represents a source ofialternating cur- 1 rent in the primary circuit of a transformer 11,12, which primary circuit also includes a device 13', for varying the amplitude of the waves of said current,fwhile the secondary coil 12, is included in the'circuit' of cable 9.

The source 10, will be operated to produm a frequency that is higher than that of the 'source 1, sot-hat at the opposite end of the system,.distinct signals transmitted through the medium of these tw'o currents may be and the circuit of receiving device 7;- this transformer being so related to the trans- 110 thelcurrent from the former 11,12, that E. M. F.s of opposite phase are generated in the circuit of the re;

ceiving device 7, and they are so ,adjusteda I to balance each other in regard to the mtensities of the E. M. F.s induced in the circuit of receiver 7.

As a further safe-guard against dlsturbing influences in the receiving-device circuit, from the source 10, a loop circuit is em ployed consisting of the capacity 16 and inductance 17, connected in parallel, and tuned-to be in resonance for the frequency of source 10, thereby oflering a great res1st ance to any residual current from source 10,

which may be due to lack'of perfect balance. A sending equipment for an extra simplex circuit is hereby created, capable of impressing an alternating .current'on' the cable .9,

' without affecting the receiving device-'7 at the corresponding end of the duplex system, or in any way of the duplex system at that end.

The receiving equipment of the superim-,

posed simplex circuit, located at the station B, will consist according to Fig. 1, in the transformer 18: 19, of which the primary 18, is in'the cable circuit, while-theseconda-ry coil 19 is in circuit with tuning condenser 20 and telephone 21.

interfering'with the operation moreover, receiving'instrument 7 being of a nature to interpret signals of'the duplex -fore received directly densers 6, 6, of the duplex equipment, is connected in an independent circuit which is coupled therewith, through. means of the transformer 24,25; said independent circuit' including the secondary coil 25'of said trans- At'the receiving end B of the simplex system, which is a sending as well as a re ceiving end of the duplex system, means;

must be employed for preventing current from source 1 from acting through the '23, is introduced with its transformer 18, 19, upon the telephone-21. To this end, an additional transformer 22, 'rimary 22 in series with the artificial cab e 8, at station B, and its secondary 23 in the circuit ofte'lephone 21. The transformer 22,- '23, is I so connected as to induce an E. M. F. opposite in phase to that induced by transformer 18, 19, and since the current from local source 1 in primary 18 which'is in the cable circuit and the current from the same source in the artificial cable 8 are exactly the same, the

effect of local source 1 acting through transformer 18, 19 upon the circuit'of telephone 21 will be neutralized. V

. In the embodiment of the invention just described, in accordance with Fig. 1, the frequency of source 10 of the superimposed simplex system must be within audition so that it can be heard directly'in the telephone 21. Current from source 1 notafi'ectthe telephone 21, first because it is of a frequency below audition and secondly,

because the circuit of telephone 21 is tuned to be in resonance for the frequency of source 10 and thus ofiers great impedance to incoming current transmitted by source 1.

Furthermore, current from source 10 will be magnitude to affect. receiving device 7 at station B, which is of much less .sensitiveness .as compared with telephone of station A will.

' the 114,808 filed by two of the applicants of Austin and Cohen. 27,

former together with the loop circuit 16, 17, and receiving device 7. Then, to counterbalance the effect of current from source 10 upon the receiving device7, a counterbal-' ance effect is produced between the circuit of source 10 and the secondary circuit which I phase and it will only be necessary to ad- .JllSt them for equality in induced E. M. F'. inorder to neutralize their effects upon the superimposed simplex system havin receiver 7; 1

Fig.3 is designed to illustrate a modification at the receiving end of the superimposed simplex system. For convenience, it is based u on the arrangement of Fig. 1, but. the modi cation is equally applicable toha t e sending equipment illustrated in F1 2. According to Fig. 3, the frequency 0 the source 10 of the simplex system, 1s either wholly below audition or not clearly within audition, so that it can not be directly interpreted in'the telephones, and thus -r e-' quires a device at the receiving'end of the simplex system to render it directly audible. Different instrumentalities may'be employed for this purpose, such for instance, as the os-. cillating audion or the ticker, described in co-pending application Serial go. t is case, namely, Messrs. in Fig. 3, represents such a device, capable of modifyin an alternating current of frequency that is below audition and rendering it audible.

That is to say, 27, represents either a ticker or an audion ing circuit of the superimposed simplex sysintroduced in the receivmenace tem, according to the arrangement of Messrs. Austin and Cohen in which 19, 20, 23 represent an oscillating circuit, 21, the telephone and 21, 26, 27, the-receiver circuit proper, which is connected with said oscillating circuit.

During the operation of the duplex and simplex systems, according to Fig. 3, the frequency of source 10 willbe higher than that of source 1, as in the embodiments of the invention illustrated, in previousfigures, but not high enough to be within audition, and hence, requiring to be modified by the instrument 27, to bring it within audition as described; v

The ticker is essentially an instrument having a metallic point dragging over the surface of a rotating metal plate, so that when introduced into an electric circuit, the irregularities on the surface of the plate cause'variations in resistance ofthe circuit, and thus, produce variations in the current a of sufliciently high rate to make the current effect audible.

An oscillating audion is an instrument for generating oscillatory currents whose frequency is determined by the electrical constants of the oscillatory circuit with which it is associated. According to the invention of Messrs. Austin and Cohen, this device is applied to a receiving circuit and made ,to bring a current below audition up to audition, in the following manner The constants of the oscillating circuit associated with the audion are adjusted; tov

bring the frequency of the oscillation within the range of audibility so that they are heard as a definite note in the telephone, and

4 the effect of the current of the received sig- 'nals, superimposed upon the normal oscillating current-of the oscillating audion,-will be to vary the intensity in accordance with the.

ale and thus render the latter "in s1 te ligible.

While we have shown but a single extra simplex circuit, superimposed upon] the duplex system, we desire it understood that i our invention is not restricted in its use to single superimposing, but may be made applicable to multiple superimposing of sim plex circuits with transmltting equi ments either at the same or at opposlte en s; this to be accomplished by the proper use of counterbalancing transformers, loop circuits and, differences in frequencies employed.

We also desire it understood that itis practicable to .have both transmitting and receiving equipments at each end of the superimposed simplex system, and thus use either end as the transmitting station, or receiving station, by merely providing means for cutting the appropriate equipments in and out at will, as for instance, at certain predetermined times, so-that simplex sending will be inone direction at one part of ble and receiving the signals of the simplex circuit by audition.

2. The improvement in the art of cable signaling, which consists in superimposing an extra, simplex circuit upon the standard duplex equipment, operating both said circuits with unbroken alternating currents of frequencies below audition but different from each other, the frequency of the simplex circuit being the higher, superimposing the current of the simplex system, upon an audion circuit which oscillates with an audible frequency, and thereby varying the in-' tensity of the audion current in accordance with the received signals, and receiving the resultant current by telephone.

3. A system-of multiplex electric signaling comprising a long distance duplex system embodying a line conductor, a source of unbroken (alternating current of low frequency, and transmitting and receiving instrumentalities at the respective ends, anda superimposed simplex systemembodying a source of unbroken alternating current of a different low frequency which is below audition, a transmitting and a receiving equipment, circuit with the same line, ada ted to sendand receive current of different c an acteristics from that. of the duplex system, and in which the receiving equipment is capable of excluding the currents of the duplex system, and means for modifying the ceiv ng end to render it readily audible.

- 4. A mu'ltiplex system of electric signaling comprising a long distance duplex cable'sys- -frequency' of the simplex system at the reteam including a receiving equipment and a I source of alternating current of low frequency at each end; and a superimposed simplex system including at one end a source of alternating current of a different frequency which is below audition and at the other end a receiving equipment capable of admitting the currento the simplex system but excluding the current of the duplex system, and comprising means for modifying the frequency of the simplex system to render it readily audible.

5. A multiplex system of electric signaling comprising a long distance duplex cable s s-' tem including a receiving equipment an a 'duplexsystem being below the limits of source of 'ye'rnating current of low fre--- quency at e ch end; and a superimposed simplex system including at one end a source of alternating current of a difierent frequency "which is below audition and at the other end 6. A multiplex system of electric signaling comprising a long distance duplex cable system including a receiving equipment and a source of alternating current at each end;-

and a' superimposed simplex system includ ing at. one end-a source of alternatin cur, rent of a different frequency which is slow audition, and-at the other end a receiving equipment capable of admitting the current of the simplex system butexcluding the "cur: rent of-the duplex system and comprising means for modifying the frequency of the simplex system to render it-readily audible; the several receiving equipments, including si 'aling devices; and the signalingdevice o cies delivered by the signaling devices 0 the audition. 4

7. A multiplexsystem ofelectric signaling comprising a duplex system including a recelvlng equipment and a source of alternating current ateach end; and a superimposed the simplex system-delivering low fre-f quencies vvithin audition, and the fre uensimplex system includin at one end a sourc'e of alternating current 0 difi'erentfrequency from that of the duplex system, and at the other end a receiving equipmentcapable of admitting the current .of the simplex system but excluding the current of the duplex system'; the frequencies of the currents transmitted through the respective systems being below audition, and the receiving equipment 40f thesimplex system including a translating device capable of converting the received energy into frequencies Within audition.

8. A multiplex system of electric signaling --comprising a duplex system including a receiving equipment anda source of alternat- -,ing current at each end; and a superimposed simplex system including at one end a. source of alternatin current of difierent frequency from that 0 the: duplex system, and at the other end a receiving e uipmcntca'pable of admitting-the current 0 the simplex system but excluding the current of the duplex system; the current of the simplex system being of lesser magnitude than that of the duplex system, the receiver of the duplex system be-' ing responsive only to a current of greater magnitude than that of the simplex system, and the receiver of the simplex system being sensitive to current'of such lesser magnitude 'plex system.

I; "LOUIS COHEN-F but tuned to exclude frequencies of the due I The foregoing specification signed at Wash ington', in the District' of Columbia.

GEORGE ownnfsouinn. -LOUIS -WINSLOW-AUSTIN.- 

